Tacit collusion is a collusion between competitors who do not explicitly exchange information but achieve an agreement about coordination of conduct.[1] There are two types of tacit collusion: concerted action and conscious parallelism.[2][3] In a concerted action also known as concerted activity,[4] competitors exchange some information without reaching any explicit agreement, while conscious parallelism implies no communication.[1][5] In both types of tacit collusion, competitors agree to play a certain strategy without explicitly saying so. It is also called oligopolistic price coordination[6] or tacit parallelism.[7]
A dataset of gasoline prices of BP, Caltex, Woolworths, Coles, and Gull from Perth gathered in the years 2001 to 2015 was used to show by statistical analysis the tacit collusion between these retailers.[8] BP emerged as a price leader and influenced the behavior of the competitors. As result, the timing of price jumps became coordinated and the margins started to grow in 2010.
^ abHarrington, Joseph E. (2012). "A theory of tacit collusion"(PDF). Working Paper, No. 588. Archived(PDF) from the original on 7 June 2022. Retrieved 24 March 2021.